1. Field of the Invention
The present invention relates to an aluminum porous body and a method of fabricating the same.
2. Description of Related Art
Aluminum porous bodies are used as heat-exchanger materials, filter materials, shock/vibration-absorbing materials, sound-insulating/absorbing materials, and the like. An aluminum porous body is fabricated usually by molding a base material (e.g., powder material, chip material, fibrous material) of pure aluminum or aluminum alloy into a desired shape and joining the contact points of the base material by sintering or brazing.
Meanwhile, a base material of pure aluminum or aluminum alloy is known as a sintering-resistant material since it generally forms a coating of alumina (Al2O3), which is thermally very stable, on a surface thereof. Therefore, in order to obtain a sintered body of a pure aluminum base material or an aluminum alloy base material, it is necessary to subject the base material to high deformation at a molding stage to break the Al2O3 coating on the surface and to promote contact between newly-formed surfaces before subjecting the base material to liquid-phase sintering in the solid-liquid coexistence region.
For example, JP-A 2004-285410 discloses an aluminum porous body having a bulk density of not less than 0.20 g/cm3 and not more than 1.20 g/cm3. This aluminum porous body is obtained by cutting an aluminum clad material formed of an aluminum or aluminum alloy material clad with a brazing filler metal of aluminum alloy to form chips containing the brazing material, by molding the chips into a predetermined shape, and by subjecting the molded piece to brazing. The contact point joining percentage between the chips is not less than 25% and less than 50%.
Unfortunately, with conventional techniques such as the one described above, it is difficult to fabricate a porous body having a complex shape since conventional techniques inevitably involve molding a base material into a desired shape by metal stamping or the like as a preliminary step prior to the sintering or brazing process. Moreover, conventional techniques tend to be costly since each change in shape requires a new stamping die.